Well, if you've never turned on iTuns Match, I can put your mind to rest on at least one issue. They are not taking up space in your iCloud account. Since it's an iTunes purchases song, it would not take up space even if you did have iTunes Match turned on.
This looks like something that happened to me on a number of songs when I upgraded to iTunes 11 on my iMac. A lot of songs started showing up doubled, with one copy showing up with a cloud (available for download) and the other local.
After a lot of digging around I discovered that the local song was alway an older purchase with DRM and lower bit rate. My theory is that the older versions of the songs were removed from the iTunes catalog. I'm guessing that rather than break my purchase history, and deny me the ability to download the song again for free, Apple linked me to newer versions of the songs over time. These were inevitably at a higher bit rate, and usually DRM free.
This probably existed before, but iTunes 11 was the first version to show your un-downloades songs inline with the local ones. So suddenly, there were a bunch of seeming duplicates.
I solved this slowly over time. I first went through my library and deleted any local song that had a duplicate in iTunes; then a hundred or so a day I downloaded the new versions. Hey, there were higher quality, and in many cases DRM free.
So even though it was a huge inconvenience, I did get free quality upgrades on a lot of music.
Back to you.
I'm guessing the same thing has happened to you. If you use iTunes on a computer, that would be the easier place to clean it up, then sync again.
If you use the iPad without syncing to iTunes, I'm not sure how to clean things up. You may have to contact iTunes support and see if they have a solution. It may require you do delete your Music library and download all your stuff again. I hope not.
Good luck.
